Hi Matt 1. You can't use USB and RS-232 parallely. So, you have to use RS-422 to hook up the AMT to your mac and USB or RS-232 to connect the AMT to your PC. Has your mac still a RS-422 connection? Likely not... Ok, then you need something like: http://www.geethree.com/stealth/index.html You can't access the AMT from both computers at the same time. After switching on the AMT only communicates with the port which sends data first. So, unfortunately there is no possibility to twitch sounds in SD when Logic is running... 2. MIDIoverLAN/MIDIPipe sounds interesting. Could work... 3. Ever thought of installing Classic/OMS and running SD under Classic. Doesn't work that bad. But with a very limitation: Either MacOSX or Classic can access the AMT. So, no possibility either to twitch sounds in SD when Logic is running. This is the way I do it. 4. Other possibility: Dealing with some MIDI data delay you can hook up two MIDI interfaces in series (one connected to your mac, one to your PC), put a MIDI merger or MIDI matrix inbetween to mix the data streams to/from your synth. cheers groba